GPS Speedometer and Odometer is a distance-measuring app for cars and bicycles. It will be used as a speed detector. 

The app features an odometer widget, which provides real-time map views and speedometer reading while displaying the speedometer heads-up display. It can be used as a speed detector and distance meter to measure the speed and distance of cars, bikes, and other vehicles.

The app is free and can be used on your mobile devices.

You can navigate around the map view to locate the location of your destination. It also displays the speed and distance as you move the car or bike.

You can use the Android Wear sensor to detect whether your car is moving or not.